title: UL31 of herpes simplex virus 1 is necessary for optimal NF-kappaB activation and expression of viral gene products.
abstract: Previous results suggested that the U(L)31 gene of herpes simplex virus 1 (HSV-1) is required for envelopment of nucleocapsids at the inner nuclear membrane and optimal viral DNA synthesis and DNA packaging. In the current study, viral gene expression and NF-κB and c-Jun N-terminal kinase (JNK) activation of a herpes simplex virus mutant lacking the U(L)31 gene, designated ΔU(L)31, and its genetic repair construct, designated ΔU(L)31-R, were studied in various cell lines. In Hep2 and Vero cells infected with ΔU(L)31, expression of the immediate-early protein ICP4, early protein ICP8, and late protein glycoprotein C (gC) were delayed significantly. In Hep2 cells, expression of these proteins failed to reach levels seen in cells infected with ΔU(L)31-R or wild-type HSV-1(F) even after 18 h. The defect in protein accumulation correlated with poor or no activation of NF-κB and JNK upon infection with ΔU(L)31 compared to wild-type virus infection. The protein expression defects of the U(L)31 deletion mutant were not explainable by a failure to enter nonpermissive cells and were not complemented in an ICP27-expressing cell line. These data suggest that pU(L)31 facilitates initiation of infection and/or accelerates the onset of viral gene expression in a manner that correlates with NF-κB activation and is independent of the transactivator ICP27. The effects on very early events in expression are surprising in light of the fact that U(L)31 is designated a late gene and pU(L)31 is not a virion component. We show herein that while most pUL31 is expressed late in infection, low levels of pU(L)31 are detectable as early as 2 h postinfection, consistent with an early role in HSV-1 infection.
authors.affiliation: C5132 Vet Med Center, New York State College of Veterinary Medicine, Cornell University, Ithaca, NY 14853, USA.
authors.forename: Kari L
authors.initials: KL
authors.lastname: Roberts
authors.forename: Joel D
authors.initials: JD
authors.lastname: Baines
mesh_terms: D000818:Animals; D002460:Cell Line; D017353:Gene Deletion; D015870:Gene Expression; D018259:Herpesvirus 1, Human / Q000254:growth & development / Q000472:pathogenicity*; D054884:Host-Pathogen Interactions; D006801:Humans; D016328:NF-kappa B / Q000378:metabolism*; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism*; D014764:Viral Proteins / Q000096:biosynthesis* / Q000235:genetics / Q000378:metabolism
chemical_list: D016328:NF-kappa B; D009687:Nuclear Proteins; C108721:UL31 protein, Human herpesvirus 1; D014764:Viral Proteins